The subject matter of the present invention relates generally to pressure tank connector apparatus and in particular to such connector apparatus including a connector fitting having an insert sleeve of harder metal than the fitting body which is crimped or otherwise bent over a tank wall portion surrounding the connector opening to form a high pressure connection of great strength. As a result, the connector apparatus is suitable for high gas pressure tanks having working pressures many times that of atmospheric pressure. The pressure tank connector apparatus of the present invention has greater strength than previous connector apparatus employing welded fittings which are welded to the tank and by using a steel insert sleeve is stronger than those crimped fittings formed entirely of aluminum alloy. However, the present connector apparatus is less expensive to manufacture than all steel connectors by virtue of molding the body portion of the fitting from aluminum alloy or other metal of less hardness than the insert sleeve. In addition, the connector apparatus is made safer by positioning the fitting body within the pressure tank so that the entire threaded portion of the connector apparatus is positioned inside the inner surface of the tank wall. Hence, there is less likelihood of damage to the connector during traffic accidents or during handling of the pressure tank before it is attached to the vehicle.
It has previously been proposed in U.S. Pat. No. 3,124,267 of Cetrone, issued Mar. 10, 1964 to provide a sealed container connector with a crimped fitting sleeve extending from a hexagonal shaped fitting body which prevents rotation of such connector. However, this connector apparatus does not employ an insert sleeve of greater hardness than the fitting body. Also, the fitting sleeve is threaded and such threaded portion extends outside of the tank wall. A plastic plug which is threaded into the passageway of the fitting sleeve and fitting body is employed to produce a seal by means of a deformable knife edge on such plastic plug. The resulting connector apparatus is not suitable for an air brake tank or other high pressure container containing gas above atmospheric pressure. Instead, it appears to have been employed as a connector for an oil drum or other non-pressurized container of liquid.
A similar teaching is shown in U.S. Pat. No. 1,718,610 of Strama, issued June 25, 1929 and in U.S. Pat. No. 1,332,686 of Reynolds, issued Mar. 2, 1920, both of such show crimped connectors but do not employ fitting sleeves of harder metal than the fitting bodies and do not position the threaded portion of the fitting entirely within the tank. Also, with the connectors of these latter patents, the crimped connection is formed on the interior of the container and the free end of the fitting sleeve extends into the tank. This has the disadvantage of requiring the positioning of a crimping punch within the tank during fastening or fastening the connector to the tank wall before the tank is formed. The resulting connector apparatus is used for metal barrels containing liquid, apparently beer barrels, but is not suitable for high pressure tanks.